Various camera bodies are equipped with a hot shoe accessory connector. A flash lighting device may be connected, directly or through an extension cord, to the hot shoe connector. The emission of flash light from the lighting device can be synchronized to an image acquisition by the camera by a synchronization signal received by the lighting device via the connection to the hot shoe connector.
A remote flash lighting device can be triggered by wireless synchronization, which has been achieved using optical and radio frequency communications to the remote flash device. Radio frequency synchronization typically involves connecting a radio transmitter to the camera body and a radio receiver to the remote flash device. The radio transmitter sends a signal to the radio receiver to trigger the remote flash device in synchronization with image acquisition by the camera. Some prior radio frequency systems include a transmitter at the remote flash device for sending a confirmation signal back to the camera side radio that indicates the flash-side radio successfully triggered of the flash device. However, a system where a remote flash device wirelessly transmits information about the flash device itself to the camera body is not known to the inventor.
Through-the-lens (TTL) flash photographic control typically involves the camera body measuring an amount of light provided by a flash lighting device during a test firing of the flash device. The measurement is performed through the lens of the camera. The camera then provides an indication to the flash device connected to the hot shoe connector of the amount of light for a main flash to be used for image acquisition. The indication of the amount of light can be made by providing start and stop signals to the flash device via the hot shoe connector. In another example, the indication of the amount of light can be made by providing a serial data via the hot shoe connector to the flash device connected thereto that includes an adjustment to the amount of light that was provided in the test flash. The flash device in the hot shoe can trigger a remote flash light by utilizing optical flash pulses (e.g., visible light or infrared light). The optical pulses can also be used to send TTL power adjustments to the remote flash device. However, the remote lighting devices do not send information about the remote lighting device to the light device in the hot shoe connector of the camera body. Additionally, this system requires that a light emitting device be connected to the hot shoe connector.